JP5899311B2 - Process for producing aminopolycarboxylates - Google Patents

Description

  The present invention relates to a process for producing aminopolycarboxylates proceeding from the corresponding polyalkanolamines, by catalytic oxidative dehydrogenation and using bases.

  Oxidative dehydrogenation of aminoalcohols using alkali metal hydroxides is usually performed using copper-containing catalysts in aqueous media under pressure and at temperatures of 140-220 ° C. The catalyst is composed of, for example, undoped or doped Raney-copper (for example, Patent Document 1 (WO 00/0666539)). As the dopant, one or more metals such as Pt, Fe, Cr, Mo, V, Bi, Sn, Sb, Pb, Ge, or Ag are usually used. In other cases, copper is applied directly or via an anchor metal (eg, Os, Ir, Rh, Pt or Pd) onto an alkali stable support (eg, US Pat. WO 03/022140) or Patent Document 3 (WO 98/50150)). Precipitated copper catalysts with further metal oxides have been described (for example Patent Document 4 (WO 03/051513) (Cu, Fe) or Patent Document 5 (EP0506973) (Cu, Zr, Ca)). Reports on reactions in noble metal systems have been made separately (for example, Patent Document 6 (EP0201957)).

In particular, the problems in the production of complexing aminopolycarboxylates such as methyl glycine acetoacetate, glutamate acetoacetate, nitrilotriacetic acid, ethylenediaminetetraacetic acid, and their salts from the corresponding polyalkanolamines are practiced corresponding to the prior art. Then, less efficient by-products are generated. This includes in particular compounds resulting from C—N or C—C— bond breakage. Using the example of an amino polycarboxylates methyl glycine acetoacetate trisodium salt (MGDA-Na _3), these are for example, carboxymethyl-alanine disodium salt (C-N bond fission) and N- methyl -N- carboxymethyl Alanine (CC bond splitting).

WO00 / 0666539 WO03 / 022140 WO98 / 50150 WO03 / 051513 EP0506973 EP0201957

  The object of the present invention is therefore to proceed from the corresponding polyalkanolamines and to produce aminopolycarboxylates by catalytic oxidative dehydrogenation (thus directly and costly further refining). It is to provide a technically simple method (a product with high purity can be obtained without performing This is equivalent to a high yield of at least 85% of the desired aminopolycarboxylate, or in other words, the by-product should be 15% by weight or less with respect to the desired product.

  In some cases, a simple work-up can be carried out first before the corresponding use: in the case of suspension processes, the catalyst can be deposited and / or filtered off. Furthermore, the desired moisture content can then be set and / or bleached, for example using hydrogen peroxide or UV-light.

  In addition to the salt (aminopolycarboxylate) itself, the corresponding aminopolycarboxylic acid can also be obtained after acidification.

  At the same time, the oxidative dehydrogenation reaction conditions should ensure the longest possible recyclability of the catalyst used.

  This task proceeds from the corresponding polyalkanolamine, by oxidative dehydrogenation in the presence of a catalyst containing 1 to 90% by weight of copper, based on the total weight of the catalyst, and in the use of a base. Process for producing a rate, firstly at a temperature in the range from 140 to 180 ° C., with partial conversion of polyalkanolamine to a reaction mixture comprising aminopolycarboxylate and this conversion Is carried out until at least 10 to 90 mol% of the polyalkanolamine has been reacted, and then the conversion is continued at the elevated temperature.

  Catalytic oxidative dehydrogenation of polyalkanolamines can be represented by the following reaction scheme:

Ｒ１＝Ｈ、−ＣＯＯＸ、但しＸ＝アルカリ−、アルカリ土類金属、又は水素
Ｒ２＝アルキル−、アルケニル−、アルキニル−、アラルキル−、ヒドロキシアルキル−、ヒドロキシアラルキル−、アルキレンカルボキシル−、アルキレンスルホナート−又はビス（ヒドロキシエチル）アミノアルキレン−基
Ｙ＝アルカリ−又はアルカリ土類金属

R1 = H, —COOX, where X = alkali-, alkaline earth metal, or hydrogen R2 = alkyl-, alkenyl-, alkynyl-, aralkyl-, hydroxyalkyl-, hydroxyaralkyl-, alkylenecarboxyl-, alkylenesulfonate- Or bis (hydroxyethyl) aminoalkylene group Y = alkali- or alkaline earth metal

This reaction can be carried out with good yield and good selectivity using Raney-copper as a catalyst. However, an economical method cannot be performed based on this catalyst system. The reason for this is that Raney-copper deactivates very quickly at high temperatures and under basic conditions and is therefore recycled only in a very limited amount. For this reason, suitable catalysts contain additional components in addition to copper in their active amounts, which ensures a long service life and stability, but at the same time compared to Rany-copper. Thus, the selectivity of dehydrogenation can be lowered. For example, implementation with a Cu / ZrO ₂ -catalyst corresponding to the prior art allows the complete reaction of polyalkanolamine (1) ALDE-Na (R 1 = COONa, R 2 = CH ₃ ), and thereby It shows high catalytic activity for oxidative dehydrogenation, however, the yield of MGDA-Na ₃ (methyl glycine acetoacetate trisodium salt) is only 72.5%. The main by-product is carboxymethylalanine disodium salt resulting from C—N-bond splitting in 25.6% yield, which is hereinafter referred to as CMA-Na ₂ . The formation of such decomposition products in oxidative dehydrogenation is known from the literature.

  In contrast, the inventor has found that the selectivity of the dehydrogenation described above can be clearly increased by selecting specific reaction conditions.

Regarding the reaction temperature , in the case of R1 = COONa and R2 = CH ₃ (hereinafter referred to as ALDE-Na ₃ ), the reaction is performed at a constant temperature of 170 ° C. than the case where the reaction is performed at a constant temperature of 190 ° C. It was found that less CMA-Na ₂ is formed as a by-product (CN bond breakage), but at the same time the reaction time required for complete conversion is considerably longer. This is disadvantageous from an economic point of view. This is because this method results in a lower space-time yield. However, CMA-Na 2 _- was to form (rather than from the intermediate product of the reaction) that was found primarily arises that a polyalkanolamine itself used was surprising. Based on this, the following is sufficient to increase the selectivity; the reaction is started at a lower temperature, and according to the desired selectivity, the fraction of reactant required for this purpose is After conversion in a certain proportion (in or to the intermediate product), the reaction temperature is increased directly or indirectly and the reaction rate is obtained with practically similar selectivity. In this way, aminopolycarboxylates can be obtained with practically similar selectivity and clearly shorter reaction times compared to reactions at constant low temperatures.

  Thus, oxidative dehydrogenation catalyzed by polyalkanolamines, according to the present invention, first, the partial conversion of polyalkanolamines is carried out at low temperatures until 10-90 mol% of the polyalkanolamines are reacted, 140 It is carried out at a temperature in the range of ˜180 ° C. and then the temperature is raised.

  Preferably, the temperature range at which the partial conversion takes place is 150 to 175 ° C, in particular 165 to 175 ° C.

  The partial conversion at low reaction temperatures is advantageously carried out until the amount of reacted polyalkanolamine is 30 to 90 mol%, preferably 50 to 80 mol%.

  After partial conversion, the temperature is preferably increased directly, i.e. in a single stage, or in stages, i.e. in multiple stages, to 180-200 [deg.] C., in particular 185-195 [deg.] C.

  Preferably, the catalytic oxidative dehydrogenation of polyalkanolamine is carried out in the presence of water as a solvent.

In addition to the effect of temperature on the selectivity of the reaction described above, the concentration of water in the reaction mixture was also found to play a role:
Water, preferably used as solvent , surprisingly has not only a diluting effect that reduces the reaction rate, but also has a negative (negative) influence on the selectivity of the reaction at increased concentrations. Thus, when using the reactant ALDE-Na in a solution of 58 wt% water, the CMA-Na ₂ -yield is already 12% (with a MGDA-Na ₃ -yield of only 50%), but more In the concentrated embodiment (37% water instead of 58% water in the reaction mixture) 81% MGDA-Na ₃ -yield is achieved and the CMA-Na ₂ -yield is similar. I found out. Furthermore, when the water content in the reaction mixture was significantly reduced, it was practically difficult to do this because the catalyst was suspended in an optimal state due to the viscous behavior of the reactants and product. Because you can't.

  Accordingly, the present invention is preferably carried out so that the concentration of water in the reaction mixture is preferably 30 to 60% by mass, particularly 40 to 55% by mass, based on the total mass of the reaction mixture.

Furthermore, it has been found that increasing the catalyst concentration in the reaction mixture not only increases the reaction rate of the oxidative dehydrogenation, but also surprisingly increases the selectivity of the reaction, eg, the amount of catalyst is 3 g / by rising to 40g / molALDE-Na from molALDE-Na (R1 = COONa, R2 = CH 3), MGDA-Na 3 in a similar transformation - yield rose to just under 90% from 72.5%, the yield CMA-Na ₂ rather become worse.

  Thus, according to the invention, only 0.40 g to 2.00 g of copper, preferably 1.00 g to 1.70 g of copper, particularly preferably 1.40 g to 1 per mole of hydroxyl group to be converted in the polyalkanolamine. The invention is preferably carried out such that the catalyst used is metered in, corresponding to .60 g of copper.

The mass ratio of MGDA-Na ₃ to CMA-Na _{2 in} the reaction product of oxidative dehydrogenation can influence MGDA-Na ₃ to be clearly advantageous by the above-mentioned conditions, and therefore The product quality is considerably improved.

  In the present invention, aminopolycarboxylate refers to an aminocarboxylate having 3 or 4 deprotonated carboxylic acid groups. Aminopolycarboxylates with 3 deprotonated carboxylic acid groups are in particular the salts of methylglycine acetoacetate and nitrotriacetic acid; aminopolycarboxylates with 4 deprotonated carboxylic acid groups Are in particular the salts of glutamic acid acetoacetic acid and ethylenediaminetetraacetic acid. Based on these structures, aminopolycarboxylates can be advantageously used as complexing agents.

  Polyalkanolamines have the general formula

（但し、Ｒ１＝ＣＯＯＸで、Ｘはアルカリ−、アルカリ土類金属、又は水素であり、及びＲ２＝アルキル−、アルケニル−、アルキニル−、アラルキル−、ヒドロキシアルキル−、ヒドロキシアラルキル−、アルキレンカルボキシル−、アルキレンスルホネートであるか、又はビス（ヒドロキシエチル）アミノアルキレン基である）
の化合物の群から選ばれることが有利である。Ｒ２は好ましくは、１〜３０個の炭素原子を有する直鎖状の、又は枝分かれしたアルキル基（これは場合により環を有していても良い）、２〜３０個の炭素原子を有する直鎖状の、又は枝分かれしたアルケニル基（これも場合により環を有していても良い）、１〜３０個の炭素原子を有する直鎖状の、又は枝分かれしたヒドロキシアルキル基、２〜３０個の炭素原子を有するアルキレンカルボキシレート基、１〜３０個の炭素原子を有するアルキレンスルホネート基、又は１〜１０個の炭素原子を有する直鎖状のビス（ヒドロキシエチル）アミノアルキレン基である。

(Where R1 = COOX, X is alkali-, alkaline earth metal, or hydrogen, and R2 = alkyl-, alkenyl-, alkynyl-, aralkyl-, hydroxyalkyl-, hydroxyaralkyl-, alkylenecarboxyl-, An alkylene sulfonate or a bis (hydroxyethyl) aminoalkylene group)
Advantageously, it is selected from the group of compounds R2 is preferably a linear or branched alkyl group having 1 to 30 carbon atoms (which may optionally have a ring), a linear chain having 2 to 30 carbon atoms. Linear or branched alkenyl groups (which may optionally also have a ring), linear or branched hydroxyalkyl groups having 1 to 30 carbon atoms, 2 to 30 carbons An alkylene carboxylate group having an atom, an alkylene sulfonate group having 1 to 30 carbon atoms, or a linear bis (hydroxyethyl) aminoalkylene group having 1 to 10 carbon atoms.

Particularly preferably, the amino acid alanine _{(R1 = COOX; R2 = CH} 3), glutamic acid _{(R1 = COOX; R2 = CH} 2 -CH 2 -COOX), and serine _{(R1 = COOX; R2 = CH} 2 -OH), or ethylenediamine _{(R1 = H; R2 = CH} 2 -N (CH 2 -CH 2 -OH) 2), or compounds derived from triethanolamine _{(R1 = H, R2 = CH} 2 -OH).

  A polyalkanolamine is a chelate compound having at least one asymmetric carbon atom, which can be used in an enantiomerically pure, non-racemic or racemic form.

  As base, preference is given to alkali or alkaline earth metal hydroxides, in particular sodium or potassium hydroxide. These are advantageously used as aqueous solutions, preferably 50% by weight.

  The reaction pressure is advantageously set so that the hydrogen formed is continuously removed. Preference is given to standard pressures to 100 bar (absolute pressure), particularly preferably 5 to 50 bar (absolute pressure) and very particularly preferably 8 to 20 bar (absolute pressure).

  The method is preferably carried out batchwise.

  Particular preference is given to processes in which the polyalkanolamine is prepared by alkoxylation of the base (parent) amine or the base amino acid and is directly dehydrogenated. Direct dehydrogenation means that separation on the equipment (substances with a boiling point above 200 ° C. at standard pressure) based on different boiling points is not performed between alkoxylation and oxidative dehydrogenation. This is simple in terms of equipment and results in a relatively good quality of the final product, saving one operation.

  Preferably, it can proceed (process) according to the method described in the European patent application with patent number EP 11162091.0. According to this method, starting from an amino acid, it reacts with ethylene oxide in the first step and is converted into an intermediate product mixture (including the corresponding dialkanolamine) and then in the second step an intermediate product The mixture is converted to the corresponding aminopolycarboxylate by catalysis using a base. Here, the amino acid is partially neutralized with 0.70-0.99 equivalents of base per acid group prior to reaction with ethylene oxide in the first step, or in the first step, A partially neutralized amino acid is used with 0.70 to 0.99 equivalents of base per acid group.

  The catalyst containing 1 to 90% by mass of copper with respect to its total mass can be used, for example, as a powder or a molded body (for example, extrudate, tablet, etc.), as an unsupported catalyst, or as a supported catalyst.

  The final product of the process can be used as an additive in industrial cleaning formulations of, for example, metals, plastiks, coating materials, or hard surfaces of glass, optionally after the simple post-treatment described at the beginning. And in the food industry, especially in alkaline cleaning formulations for bottle cleaning in the beverage industry, and in the butter cheese mill, beer factory, food storage industry, bakery industry, sugar industry, fat processing industry, and meat processing industry In alkaline cleaning formulations, dishwashing formulations, especially machine dishwashers, household cleaning phosphorus-free compositions, or commercial premises such as large kitchens or restaurants, bleach solutions, paper industry, photo bleach, In bleach cleaning solutions, in textile industry pretreatment and bleaching, in electrolyte cleaning solutions for masking heavy metals that contaminate, in alkaline cleaning formulations, and in copper, iron, manganese And / or defects of heavy metals such as zinc complex to repair, is used in the field of plant foods. In principle, the use is advantageous in all places where precipitation of calcium-, manganese-, or heavy-metal salts is prevented in a technical manner and therefore needs to be avoided (kettles, pipes, spray containers, or Usually, precipitation on smooth surfaces and avoiding deposition). In addition, aminopolycarboxylates are used to stabilize phosphate in alkaline degreasing solutions and to prevent precipitation of lime soap, thereby preventing “fogging” of non-ferrous surfaces and alkaline It can also be used to extend the life (duration) of the cleaning solution (bath). Furthermore, they have been found to be usable as builder and preservatives in powder or liquid detergent formulations for textile cleaning. In soaps, they prevent oxidative degradation due to metal catalysis, which is also true in pharmaceuticals and cosmetics and foods.

  EXAMPLES Hereinafter, the present invention will be described in detail using examples, but these examples do not limit the present invention.

Preparation of aqueous polyalkanolamine-starting solution 4.365 kg (49.00 mol) of alanine is suspended in 2.623 kg of water and 3.897 kg (49.00 mol) of 50.3 wt% sodium hydroxide solution Was added. The resulting mixture was inserted into a 20 L autoclave (2.4610 material) and after appropriate deactivation, nitrogen was injected to 20 bar. Next, 4.749 kg (107.8 moles) of ethylene oxide was added at 40-45 ° C. within 12.5 hours and further stirred at this temperature for 3 hours. After removing unreacted ethylene oxide residues, the autoclave was emptied. In this way, 15.634 kg of aqueous reaction product was obtained as a clear, colorless viscous solution.

Comparative Example 1:
Oxidative dehydrogenation using Cu / ZrO ₂ as catalyst 314 g (0.99 mol relative to alanine) of the above-mentioned aqueous polyalkanolamine starting solution was converted to 197.9 g (2.39 mol) 50% by weight hydroxylation It was first inserted into a 1.7 L autoclave (2.4610 material) together with sodium solution, 32 g water, and 3 g Cu / ZrO ₂ (reworked from patent DE 3505208). The reactor was closed, flushed with nitrogen to 5 bar, and then the reactor was heated to 190 ° C. within 2.25 hours. This temperature was maintained for 72 hours. The stirring speed was 500 rpm over the entire test period. The generated hydrogen was continuously discharged through a 10 bar pressure relief valve. At the end of the test, the reactor was purged with nitrogen at room temperature, the reaction product was diluted with 411 g of water, and the reactor was emptied. The product was obtained as a clear, colorless, viscous solution. Using HPLC, the theoretical yield (= selectivity × conversion) of methylglycine-N, N-acetoacetic acid trisodium salt (MGDA-Na ₃ ) relative to the alanine used is 72.5% Measured. For the alanine used, carboxymethyl alanine - theoretical yield of disodium salt (CMA-Na ₂₎ was 25.6%. Therefore, the ratio of the obtained mass of MGDA-Na _{3 to} the obtained mass of CMA-Na ₂ was 1: 0.25.

Comparative Example 2:
Oxidative dehydrogenation using Cu / ZrO ₂ as catalyst 316 g (0.99 mol relative to alanine) of the aqueous polyalkanolamine starting solution described above was added to 181.6 g (2.27 mol) 50 wt. It was first inserted into a 1.7 L autoclave (2.4610 material) together with sodium solution, 32 g water, and 30 g Cu / ZrO ₂ (reworked from patent DE 3505208). The reactor was closed, flushed with nitrogen to 5 bar, and then the reactor was heated to 190 ° C. within 2.25 hours. This temperature was maintained for 16 hours. The stirring speed was 500 rpm over the entire test period. The generated hydrogen was continuously discharged through a 10 bar pressure relief valve. At the end of the test, the reactor was purged with nitrogen at room temperature, the reaction product was diluted with 407 g of water, and the reactor was emptied. The product was obtained as a clear, colorless, viscous solution. Using HPLC, the theoretical yield (= selectivity × conversion) of methylglycine-N, N-acetoacetic acid trisodium salt (MGDA-Na ₃ ) relative to the alanine used is 85.8% Measured. For the alanine used, carboxymethyl alanine - theoretical yield of disodium salt (CMA-Na ₂₎ was 8.6%. Therefore, the ratio of the obtained mass of MGDA-Na _{3 to} the obtained mass of CMA-Na ₂ was 1: 0.07. The space-time yield was 7.42 g / l ^* h.

Comparative Example 3:
Oxidative dehydrogenation using Cu / ZrO ₂ as catalyst 316 g (0.99 mol relative to alanine) of the aqueous polyalkanolamine starting solution described above was added to 181.9 g (2.28 mol) 50% by weight hydroxylation. It was first inserted into a 1.7 L autoclave (2.4610 material) together with sodium solution, 32 g water, and 30 g Cu / ZrO ₂ (reworked from patent DE 3505208). The reactor was closed, flushed with nitrogen to 5 bar, and then the reactor was heated to 180 ° C. within 2.25 hours. This temperature was maintained for 24 hours. The stirring speed was 500 rpm over the entire test period. The generated hydrogen was continuously discharged through a 10 bar pressure relief valve. At the end of the test, the reactor was purged with nitrogen at room temperature, the reaction product was diluted with 400 g of water, and the reactor was emptied. The product was obtained as a clear, colorless, viscous solution. Using HPLC, the theoretical yield (= selectivity × conversion) of methylglycine-N, N-acetoacetic acid trisodium salt (MGDA-Na ₃ ) relative to the alanine used is 88.1% Measured. For the alanine used, carboxymethyl alanine - theoretical yield of disodium salt (CMA-Na ₂₎ was 6.8%. Therefore, the ratio of the obtained mass of MGDA-Na _{3 to} the obtained mass of CMA-Na ₂ was 1: 0.05. The space-time yield was 5.30 g / l ^* h.

Comparative Example 4:
Oxidative dehydrogenation using Cu / ZrO ₂ as catalyst 316 g (0.99 mol relative to alanine) of the aqueous polyalkanolamine starting solution described above was converted to 181.1 g (2.26 mol) 50% by weight hydroxylation. It was first inserted into a 1.7 L autoclave (2.4610 material) together with sodium solution, 32 g water, and 30 g Cu / ZrO ₂ (reworked from patent DE 3505208). The reactor was closed, flushed with nitrogen to 5 bar, and then the reactor was heated to 170 ° C. within 2.25 hours. This temperature was maintained for 60 hours. The stirring speed was 500 rpm over the entire test period. The generated hydrogen was continuously discharged through a 10 bar pressure relief valve. At the end of the test, the reactor was purged with nitrogen at room temperature, the reaction product was diluted with 444 g of water, and the reactor was emptied. The product was obtained as a clear, colorless, viscous solution. Using HPLC, the theoretical yield of methylglycine-N, N-acetoacetic acid trisodium salt (MGDA-Na ₃ ) relative to the alanine used is 89.6% (= selectivity × conversion) Measured. For the alanine used, carboxymethyl alanine - theoretical yield of disodium salt (CMA-Na ₂₎ was 4.3%. Therefore, the ratio of the obtained mass of MGDA-Na _{3 to} the obtained mass of CMA-Na ₂ was 1: 0.03. The space-time yield was 2.27 g / l ^* h.

Comparative Examples 2-4 show that the practice of the oxidative dehydrogenation of a lower reaction temperature, increases the selectivity of MGDA-Na ₃ as a result. At the same time, however, this clearly increases the reaction time and reduces the space-time yield.

Example 1 (according to the invention):
Oxidative dehydrogenation using Cu / ZrO ₂ as catalyst 316 g (0.99 mol relative to alanine) of the aqueous polyalkanolamine starting solution described above was added to 182.3 g (2.28 mol) 50% by weight hydroxylation. It was first inserted into a 1.7 L autoclave (2.4610 material) together with sodium solution, 32 g water, and 30 g Cu / ZrO ₂ (reworked from patent DE 3505208). The reactor was closed, flushed with nitrogen to 5 bar, and then the reactor was heated to 170 ° C. within 2.25 hours. This temperature was maintained for 12 hours, after which 90 mol% of the polyalkanolamine had reacted. Thereafter, it was heated to 180 ° C. within 30 minutes and then kept at this temperature for 4 hours. This was followed by heating to 190 ° C. within 30 minutes and then holding this temperature for 3 hours. The stirring speed was 500 rpm over the entire test period. The generated hydrogen was continuously discharged through a 10 bar pressure relief valve. At the end of the test, the reactor was purged with nitrogen at room temperature, the reaction product was diluted with 419 g of water, and the reactor was emptied. The product was obtained as a clear, colorless, viscous solution. Using HPLC, the theoretical yield of methylglycine-N, N-acetoacetic acid trisodium salt (MGDA-Na ₃ ) based on alanine used (= selectivity × conversion) is 89.4% Measured. For the alanine used, carboxymethyl alanine - theoretical yield of disodium salt (CMA-Na ₂₎ was 5.0%. Therefore, the ratio of the obtained mass of MGDA-Na _{3 to} the obtained mass of CMA-Na ₂ was 1: 0.04. The space-time yield was 6.34 g / l ^* h.

Example 2 (according to the invention):
Oxidative dehydrogenation using Cu / ZrO ₂ as catalyst 316 g (0.99 mol relative to alanine) of the aqueous polyalkanolamine starting solution described above was 182.0 g (2.28 mol) 50% by weight hydroxylation It was first inserted into a 1.7 L autoclave (2.4610 material) together with sodium solution, 32 g water, and 30 g Cu / ZrO ₂ (reworked from patent DE 3505208). The reactor was closed, flushed with nitrogen to 5 bar, and then the reactor was heated to 170 ° C. within 2.25 hours. This temperature was maintained for 6 hours, after which 70 mol% of the polyalkanolamine had reacted. Thereafter, it was heated to 180 ° C. within 30 minutes and then kept at this temperature for 4 hours. This was followed by heating to 190 ° C. within 30 minutes and then holding this temperature for 3 hours. The stirring speed was 500 rpm over the entire test period. The generated hydrogen was continuously discharged through a 10 bar pressure relief valve. At the end of the test, the reactor was purged with nitrogen at room temperature, the reaction product was diluted with 394 g of water, and the reactor was emptied. The product was obtained as a clear, colorless, viscous solution. Using HPLC, the theoretical yield (= selectivity × conversion) of methylglycine-N, N-acetoacetic acid trisodium salt (MGDA-Na ₃ ) based on alanine used is 90.0% Measured. For the alanine used, carboxymethyl alanine - theoretical yield of disodium salt (CMA-Na ₂₎ was 5.2%. Therefore, the ratio of the obtained mass of MGDA-Na _{3 to} the obtained mass of CMA-Na ₂ was 1: 0.04. The space-time yield was 8.75 g / l ^* h.

Example 3 (according to the invention):
Oxidative dehydrogenation using Cu / ZrO ₂ as catalyst 316 g (0.99 mol relative to alanine) of the aqueous polyalkanolamine starting solution described above was 182.0 g (2.28 mol) 50% by weight hydroxylation It was first inserted into a 1.7 L autoclave (2.4610 material) together with sodium solution, 32 g water, and 30 g Cu / ZrO ₂ (reworked from patent DE 3505208). The reactor was closed, flushed with nitrogen to 5 bar, and then the reactor was heated to 170 ° C. within 2.25 hours. This temperature was maintained for 6 hours, after which 70 mol% of the polyalkanolamine had reacted. Thereafter, it was heated to 180 ° C. within 30 minutes and then kept at this temperature for 2 hours. This was followed by heating to 190 ° C. within 30 minutes and then holding this temperature for 3 hours. The stirring speed was 500 rpm over the entire test period. The generated hydrogen was continuously discharged through a 10 bar pressure relief valve. At the end of the test, the reactor was purged with nitrogen at room temperature, the reaction product was diluted with 423 g of water, and the reactor was emptied. The product was obtained as a clear, colorless, viscous solution. Using HPLC, the theoretical yield of methylglycine-N, N-acetoacetic acid trisodium salt (MGDA-Na ₃ ) relative to the alanine used is 88.8% (= selectivity × conversion) Measured. For the alanine used, carboxymethyl alanine - theoretical yield of disodium salt (CMA-Na ₂₎ was 5.6%. The ratio of the obtained mass of MGDA-Na _{3 to} the obtained mass of CMA-Na ₂ was 1: 0.04. The space-time yield was 9.84 g / l ^* h.

  Examples 1-3 show that the process of the present invention shortens the reaction time and is equivalent to a valuable product (compared to a constant process at lower temperatures and correspondingly longer reaction times). Yielded a yield of.

Comparative Example 5:
Oxidative dehydrogenation using Cu / ZrO ₂ as catalyst 316 g (0.99 mol relative to alanine) of the aqueous polyalkanolamine starting solution described above was added to 182.4 g (2.28 mol) 50% by weight hydroxylation. It was first inserted into a 1.7 L autoclave (2.4610 material) together with sodium solution, 182 g water, and 10 g Cu / ZrO ₂ (rework of patent DE 3505208). The reactor was closed, flushed with nitrogen to 5 bar, and then the reactor was heated to 190 ° C. within 2.25 hours. This temperature was maintained for 16 hours. The stirring speed was 500 rpm over the entire test period. The generated hydrogen was continuously discharged through a 10 bar pressure relief valve. At the end of the test, the reactor was purged with nitrogen at room temperature, the reaction product was diluted with 256 g of water, and the reactor was emptied. The product was obtained as a clear, colorless, viscous solution. Using HPLC, the theoretical yield (= selectivity × conversion) of methylglycine-N, N-acetoacetic acid trisodium salt (MGDA-Na ₃ ) relative to the alanine used is 49.4% Measured. For the alanine used, carboxymethyl alanine - theoretical yield of disodium salt (CMA-Na ₂₎ was 12.9%. The ratio of the obtained mass of MGDA-Na _{3 to} the obtained mass of CMA-Na ₂ was 1: 0.18.

Comparative Example 6:
Oxidative dehydrogenation using Cu / ZrO ₂ as catalyst 316 g (0.99 mol relative to alanine) of the aqueous polyalkanolamine starting solution described above was added to 181.9 g (2.28 mol) 50% by weight hydroxylation. It was first inserted into a 1.7 L autoclave (2.4610 material) together with sodium solution, 32 g water, and 10 g Cu / ZrO ₂ (patent DE 3505208 reworked). The reactor was closed, flushed with nitrogen to 5 bar, and then the reactor was heated to 190 ° C. within 2.25 hours. This temperature was maintained for 16 hours. The stirring speed was 500 rpm over the entire test period. The generated hydrogen was continuously discharged through a 10 bar pressure relief valve. At the end of the test, the reactor was purged with nitrogen at room temperature, the reaction product was diluted with 425 g of water, and the reactor was emptied. The product was obtained as a clear, colorless, viscous solution. Using HPLC, the theoretical yield (= selectivity × conversion) of methylglycine-N, N-acetoacetic acid trisodium salt (MGDA-Na ₃ ) based on alanine used is 76.2% Measured. For the alanine used, carboxymethyl alanine - theoretical yield of disodium salt (CMA-Na ₂₎ was 16.0%. The ratio of the obtained mass of MGDA-Na _{3 to} the obtained mass of CMA-Na ₂ was 1: 0.15.

Comparative Example 7:
Oxidative dehydrogenation using Cu / ZrO ₂ as catalyst 253 g (0.98 mol relative to alanine) of the above-mentioned aqueous polyalkanolamine starting solution (concentrated by distillation) was 182.3 g (2.28 mol) It was first inserted into a 1.7 L autoclave (2.4610 material) together with 50% by weight sodium hydroxide solution, 37 g water, and 10 g Cu / ZrO ₂ (reworked from patent DE 3505208). The reactor was closed, flushed with nitrogen to 5 bar, and then the reactor was heated to 190 ° C. within 2.25 hours. This temperature was maintained for 16 hours. The stirring speed was 500 rpm over the entire test period. The generated hydrogen was continuously discharged through a 10 bar pressure relief valve. At the end of the test, the reactor was purged with nitrogen at room temperature, the reaction product was diluted with 431 g of water, and the reactor was emptied. The product was obtained as a clear, colorless, viscous solution. Using HPLC, the theoretical yield (= selectivity × conversion) of methylglycine-N, N-acetoacetic acid trisodium salt (MGDA-Na ₃ ) relative to the alanine used is 81.8% Measured. For the alanine used, carboxymethyl alanine - theoretical yield of disodium salt (CMA-Na ₂₎ was 13.9%. The ratio of the obtained mass of MGDA-Na _{3 to} the obtained mass of CMA-Na ₂ was 1: 0.12.

Comparative Example 8:
Oxidative dehydrogenation using Cu / ZrO ₂ as catalyst 274 g (0.98 mol relative to alanine) of the aqueous polyalkanolamine starting solution described above (concentrated by distillation), 182.6 g (2.28 mol) It was first inserted into a 1.7 L autoclave (2.4610 material) together with 50% by weight sodium hydroxide solution and 10 g Cu / ZrO ₂ (reworked from patent DE 3505208). The reactor was closed, flushed with nitrogen to 5 bar, and then the reactor was heated to 190 ° C. within 2.25 hours. This temperature was maintained for 16 hours. The stirring speed was 500 rpm over the entire test period. The generated hydrogen was continuously discharged through a 10 bar pressure relief valve. At the end of the test, the reactor was purged with nitrogen at room temperature, the reaction product was diluted with 471 g of water, and the reactor was emptied. The product was obtained as a clear, colorless, viscous solution. Using HPLC, the theoretical yield (= selectivity × conversion) of methylglycine-N, N-acetoacetic acid trisodium salt (MGDA-Na ₃ ) relative to the alanine used is 70.4% Measured. For the alanine used, carboxymethyl alanine - theoretical yield of disodium salt (CMA-Na ₂₎ was 7.8%. The ratio of the obtained mass of MGDA-Na _{3 to} the obtained mass of CMA-Na ₂ was 1: 0.08.

  In Comparative Examples 5 to 8, the water content in the reaction mixture plays an important role because of the selectivity of oxidative dehydrogenation, but sufficient selectivity is obtained only by adjusting the amount of water. Indicates that it cannot be done.

Comparative Example 9:
Oxidative dehydrogenation using Cu / ZrO ₂ as catalyst 316 g (0.99 mol relative to alanine) of the aqueous polyalkanolamine starting solution described above was converted to 181.7 g (2.27 mol) 50 wt% hydroxylation. It was first inserted into a 1.7 L autoclave (2.4610 material) together with sodium solution, 32 g water, and 10 g Cu / ZrO ₂ (patent DE 3505208 reworked). The reactor was closed, flushed with nitrogen to 5 bar, and then the reactor was heated to 190 ° C. within 2.25 hours. This temperature was maintained for 16 hours. The stirring speed was 500 rpm over the entire test period. The generated hydrogen was continuously discharged through a 10 bar pressure relief valve. At the end of the test, the reactor was purged with nitrogen at room temperature, the reaction product was diluted with 404 g of water, and the reactor was emptied. The product was obtained as a clear, colorless, viscous solution. Using HPLC, the theoretical yield of methylglycine-N, N-acetoacetic acid trisodium salt (MGDA-Na ₃ ) relative to the alanine used is 77.2% (= selectivity × conversion) Measured. For the alanine used, carboxymethyl alanine - theoretical yield of disodium salt (CMA-Na ₂₎ was 18.2%. The ratio of the obtained mass of MGDA-Na _{3 to} the obtained mass of CMA-Na ₂ was 1: 0.17.

Comparative Example 10:
Oxidative dehydrogenation using Cu / ZrO ₂ as catalyst 316 g (0.99 moles relative to alanine) of the above-mentioned aqueous polyalkanolamine starting solution was 182.1 g (2.28 moles) 50% by weight hydroxylation It was first inserted into a 1.7 L autoclave (2.4610 material) together with sodium solution, 32 g water, and 20 g Cu / ZrO ₂ (patent DE 3505208 reworked). The reactor was closed, flushed with nitrogen to 5 bar, and then the reactor was heated to 190 ° C. within 2.25 hours. This temperature was maintained for 16 hours. The stirring speed was 500 rpm over the entire test period. The generated hydrogen was continuously discharged through a 10 bar pressure relief valve. At the end of the test, the reactor was purged with nitrogen at room temperature, the reaction product was diluted with 411 g of water, and the reactor was emptied. The product was obtained as a clear, colorless, viscous solution. Using HPLC, the theoretical yield (= selectivity × conversion) of methylglycine-N, N-acetoacetic acid trisodium salt (MGDA-Na ₃ ) based on alanine used is 77.8% Measured. For the alanine used, carboxymethyl alanine - theoretical yield of disodium salt (CMA-Na ₂₎ was 11.3%. The ratio of the obtained mass of MGDA-Na _{3 to} the obtained mass of CMA-Na ₂ was 1: 0.10.

Comparative Example 11:
Oxidative dehydrogenation using Cu / ZrO ₂ as catalyst 316 g (0.99 mol relative to alanine) of the aqueous polyalkanolamine starting solution described above was added to 181.6 g (2.27 mol) 50 wt. It was first inserted into a 1.7 L autoclave (2.4610 material) together with sodium solution, 32 g water, and 30 g Cu / ZrO ₂ (reworked from patent DE 3505208). The reactor was closed, flushed with nitrogen to 5 bar, and then the reactor was heated to 190 ° C. within 2.25 hours. This temperature was maintained for 16 hours. The stirring speed was 500 rpm over the entire test period. The generated hydrogen was continuously discharged through a 10 bar pressure relief valve. At the end of the test, the reactor was purged with nitrogen at room temperature, the reaction product was diluted with 407 g of water, and the reactor was emptied. The product was obtained as a clear, colorless, viscous solution. Using HPLC, the theoretical yield (= selectivity × conversion) of methylglycine-N, N-acetoacetic acid trisodium salt (MGDA-Na ₃ ) relative to the alanine used is 85.8% Measured. For the alanine used, carboxymethyl alanine - theoretical yield of disodium salt (CMA-Na ₂₎ was 8.6%. The ratio of the obtained mass of MGDA-Na _{3 to} the obtained mass of CMA-Na ₂ was 1: 0.07.

Comparative Example 12:
Oxidative dehydrogenation using Cu / ZrO ₂ as catalyst 316 g (0.99 mol relative to alanine) of the aqueous polyalkanolamine starting solution described above is 181.8 g (2.27 mol) 50% by weight of hydroxylation It was first inserted into a 1.7 L autoclave (2.4610 material) together with sodium solution, 32 g water, and 40 g Cu / ZrO ₂ (reworked from patent DE 3505208). The reactor was closed, flushed with nitrogen to 5 bar, and then the reactor was heated to 190 ° C. within 2.25 hours. This temperature was maintained for 16 hours. The stirring speed was 500 rpm over the entire test period. The generated hydrogen was continuously discharged through a 10 bar pressure relief valve. At the end of the test, the reactor was purged with nitrogen at room temperature, the reaction product was diluted with 400 g of water, and the reactor was emptied. The product was obtained as a clear, colorless, viscous solution. Using HPLC, the theoretical yield (= selectivity × conversion) of methylglycine-N, N-acetoacetic acid trisodium salt (MGDA-Na ₃ ) based on alanine used is 89.5% Measured. For the alanine used, carboxymethyl alanine - theoretical yield of disodium salt (CMA-Na ₂₎ was 7.5%. The ratio of the obtained mass of MGDA-Na _{3 to} the obtained mass of CMA-Na ₂ was 1: 0.06.

  Comparative Examples 9-12 show that increasing the amount of catalyst used increases not only the rate of oxidative dehydrogenation but also the selectivity. However, sufficient selectivity cannot be obtained only by adjusting the catalyst amount.

Claims (13)

Proceeding from polyalkanolamines, the corresponding aminopolycarboxylates are prepared by oxidative dehydrogenation in the presence of a catalyst containing 1 to 90% by weight of copper, based on the total weight of the catalyst, and with the use of a base A method for
First, at a temperature in the range of 140-180 ° C., a partial conversion of the polyalkanolamine to the reaction mixture containing the aminopolycarboxylate is performed, and this conversion is performed at least 10-90 moles of the polyalkanolamine. % Until it is reacted and then the conversion is continued at the elevated temperature. Alkanolamine has the formula:

(However,
R1 = H, or COOX in which X represents an alkali metal, alkaline earth metal, or hydrogen, and R2 = alkyl-, alkenyl-, alkynyl-, aralkyl-, hydroxyalkyl-, hydroxyaralkyl-, alkylenecarboxyl- , Alkylene sulfonate-, or bis (hydroxyethyl) aminoalkylene-group).
The process according to claim 1, characterized in that it is selected from the group of polyalkanolamines. R1 = H, and R2 = _-CH 2 OH, or R1 = COOX and R2 = CH _3, or R1 = COOX and _R2 = _CH 2 -CH 2 -COOX, or R1 = H and R2 ₌ CH 2 -N (C The method according to claim ₂ , wherein ₂ H ₄ OH) ₂ . The method according to any one of claims 1 to 3, wherein a temperature range in which the partial conversion is performed is 150 to 175 ° C. The method according to claim 4, wherein a temperature range in which the partial conversion is performed is 165 to 175 ° C. The method according to any one of claims 1 to 5 , wherein the amount of polyalkanolamine reacted before raising the reaction temperature is 30 to 90 mol % . The method according to any one of claims 1 to 6 , wherein the temperature is increased directly or stepwise to 180 to 200 ° C after partial conversion. The method according to any one of claims 1 to 7 , wherein the catalytic deoxidation is performed in the presence of water as a solvent. The method according to claim 8 , wherein the concentration of water in the reaction mixture is 30 to 80 % by mass. The amount of catalyst used per 1 mol of hydroxyl group to be converted in the polyalkanolamine, according to claim 1-9, characterized in that the metered to correspond to copper 0.40g~2.00g The method according to any one of the above. 11. The amount of catalyst used is metered in to correspond to 1.00 g to 1.70 g of copper per mole of hydroxyl groups to be converted in the polyalkanolamine. Method. 12. The amount of catalyst used is metered in to correspond to 1.40 g to 1.60 g of copper per mole of hydroxyl groups to be converted in the polyalkanolamine. Method. As polyalkanolamine, an intermediate product comprising a dialkanolamine obtained by ethoxylation of an amino acid is used, said amino acid being reacted with 0.70-0.99 equivalents of base per acid group prior to reaction with ethylene oxide. Amino acids that are fed into the partial neutralization or already partially neutralized with 0.70 to 0.99 equivalents of base per acid group are fed into the reaction with ethylene oxide the method according to any one of claims 1 to 12.